Load equalizer



Feb. 6, 1968 R. c. PETERSON LOAD EQUALI ZEE 3 She'ets-Sheet 1 Filed Oct. 22, 1965 /m/,w raz' ,Pa-fer6' 202175.44/

Feb. 6, 1968 R. c. PETERSON 3,367,209

LOAD EQUALIZER Filed oct. 22, lees 3 Sheets-Sheet 2 Feb- 6, 1958 R. c. PETERSON '3,367,209

LOAD EQUALIZER Filed oct. 22, 1965 3 sheetsheet s United States Patent itice 3,367,2@9 Patented Feb.. 6, l

3,367,209 LOAD EQUALIZER Robert C. Peterson, 104 Santa Rita, Odessa, Tex. 7976) Filed Oct. 22, 1965, Ser. No. 502,666 10 Claims. (Cl. 712-573) This invention relates to load equalizers, and more particularly to load equalizers for containers to be rotated about a vertical axis at a fast rate to extract liquid from material within the container. More specifically the invention is concerned with automatically balancing the load distribution in rotary tub machinery for extracting liquid from material within the tub by rotation about a vertical axis, typically as in a vertical tub automatic washing machine. This invention is an improvement over my pending application Ser. No. 425,551, tiled Jan. 14, 1965.

In vertical tub automatic washing machines, vibration and gyration of the tub occurs during the spinning or extraction cycle because the center of gravity, under unequal distribution of the clothing load within the tub, shifts from the geometrical axis of rotation to a new axis. Various mounting and drive mechanism have been devised to reduce the effects of unequal distribution and shifting of the center of gravity without success in eliminating the unbalance. Of course, below the critical rotating speed gyration of the Washer tub occurs and above the critical speed the axis of rotation will shift to a new axis of rotation distinct from the normal or geometrical axis. The degree of shift from the normal axis of rotation depends on the degree of unbalance of the clothing load. Thus, the tub tends to rotate about the new center of gravity for the tub which depends on the amount of unequal distribution of the clothing load.

Previous methods of dealing with the unbalance problern have included placing a tubular ring about the outer periphery of the tub and filling the ring with loosely packed steel wool and liquid. The deciency in this system occurs below the critical speed in that such technique increases gyration. The balancing tubular ring idea was further explored with the result that a thixotropic rnaterial was added to the ring which remained gelled below the critical speed and became uid above the critical speed. The problems and proposed solutions are fully set forth in US. Patent No. 2,836,083. Moreover, such patent adequately describes typical vertical tub automatic washing machines.

in any rotating machine, a most important example of forced vibration is found in the lateral vibration of the rotating mass. An eccentric rotating mass center will induce lateral vibrations in the mass if the center of gravity of the mass is not at the geometrical axis. The effect is to create a rotating centrifugal force with an X and Y component. If the resultant restoring force due to bending of the mass body (a shaft) and deilecting of the bearings is the same, the motions have the same frequency and resonance occurs. The angular velocity under such condition is the critical speed and the amplitude may become very large. Below critical speed the centrifugal force rotates in the same direction as the mass body and above critical speed in the opposite direction as the mass body. A more detailed discussion of forced vibration and its relationship to critical speed or resonance speed may be obtained from among others the following publications: Mechanical Vibrations by I. P. D. Harlog, fourth edition, 1956, McGraw-Hill Book Company, Inc. especially chapter 2, section 2.7 entitled Forced Vibration Without Damping; Practical Solution of Torsional Vibration, volume ll, Amplitude Calculations, by Wiker Wilson, 1963; and Schaums Outline of Theory and Problems of Machine Design by Hall, Holowenks & Laughlin, Schaum Publishing Co.

The use of thixotropic material in a tubular ring still fails to operate as a load equilizer or balancer below the critical speed of the rotary tub because the material is a gel. As disclosed in the aforementioned patent, the use of thixotropic material must be such that it remains gelled through the critical speed to prevent adding to the unbalanced gyrations. Furthermore, thixotropic materials suitable for use in the balancing ring are organic materials such as acetylene tetra bromide, and hence are undesirable.

Consequently, in order to decrease unbalance during the period of gyration below the critical speed, it is essential to dampen movement of the equalizing mass without complete immobility thereof. Thus, as the washer tub begins to gyrate, slow movement of the mass tends to shift and equalize the tub load without overshifting and adding to excessive gyration. Heretofore no mechanism or load equalizer has been proposed which functions to equalize the washer load during gyration occurring below the critical speed.

The present invention employs a taper mass ring with a stop member encircling the spin tub. The mass ring is mounted on three support brackets or guides of a low friction material such as Teflon or perhaps other plastic. The taper ring may be provided with a riding rib to reduce friction. A spring loaded mass brake having a stop lug is positioned at one of the support brackets for each taper ring utilized. Since the mass brake is provided to stop a taper ring in a particular location on the peripheral face adjacent thereto, the mass brake for each taper ring is spaced mutually equidistant from other mass brakes. The mass brakes hold the taper rings in a predetermined position preventing relative rotation of the taper rings with respect to the spin tub. At a preselected rotary speed of the spin tub, the mass brakes release the taper mass rings permitting relative rotation of the mass rings with respect to the washer spin tub. When the mass ring is released, the forces created by an unbalanced clothes load causes the taper mass rings to rotate relative to the spin tub positioning the mass rings to equalize the unbalanced load. After a spin cycle has been completed the mass brakes engage and lock each taper mass ring in its initial position with the mass ring weight equally distributed about the spin tub. Hence, for each spin cycle the mass rings equally distribute their weight about the spin tub until the mass brake is released. In this manner, the taper rings may be adjusted to operate at Some rotary speed of the spin tub below, near, at or above the critical rotary speed where gyration occurs, and thereby minimize gyration.

It will be appreciated that various different arrangements of the positive stop taper mass ring and centrifugal rnass brake are possible to achieve the unique features of the inventive construction. Moreover, the number of taper rings is preferable three, yet perhaps one could be used and certainly two or more could be used.

It is therefore an important object of the invention to provide a load equalizing member for rotatable containers in centrifuging machines, yet does not accentuate gyration near the critical rotating speed;

lt is another object of the invention to provide a load equalizer for vertical spin containers in centrifuging machines for dampening vibration and controliing vibration, operating through and beyond the critical speed without accentuating gyration;

It is another object of the invention to provide a load balancing system for centrifuging machine containers which includes movable taper mass rings supported for rotation around the periphery of the container to equalize unbalance forces of a load undergoing centrifuging;

It is another object of the invention to provide a load equalizer including unsymmetrical mass rings and mass brakes for vertical spin automatic washing machines for countervailing unequal load distribution during spin cycles, yet does not accentuate gyration near the critical rotating Speed;

It is yet another object of the invention to provide a load equalizer for a vertical spin tub automatic washer that utilizes a shifting unsymmetrical mass ring to odset any unequal load distribution in the tub during spin cycles;

It is still another object of the invention to provide a balance system for vertical spin tub automatic washers for dampening and controlling vibration active through and beyond the critical speed Without accentuating tub gyration and suppressing such gyration;

It is still yet another object of the invention to provide a balancing system for vertical spin tub automatic washers which includes moving unsymmetrical mass members encircling the upper outer periphery of the spin tub to equalize the load distribution;

These and other objects and advantages of the invention will be more fully appreciated from the ensuing description taken in conjunction with the appended claims and the drawings wherein:

FIG. 1 is a partially sectioned side view of a washer including the invention;

FIG. 2 is a sectional view taken along the line 2-2 of FIG. l;

FIG. 3 is a fragmentary sectional view of the taper mass ring appertaining to the invention;

FIG. 4 is a plane View, partly in section, of the load equalizer tubular ring;

FIG. 5a is a fragmentary'perspective view of the unsymmetrical mass ring appertaining to the invention;

FIG. 5b depicts in a fragmentary sectional view another unsymmetrical mass ring;

FIG. 6 is an enlarged fragmentary view of the mass brake member engaged with the unsymmetrical variable mass ring appertaining to the invention;

FIG. 7 depicts a face lock mass brake member appertaining to the invention.

FIG. 8 is a partially sectional side view of a washer having three mass rings appertaining to the invention;

FIG. 9 is a sectional view taken along line 9 9 of FIG. 8 depicting the equidistribution of mass ring, brackets and brakes;

FIG. l0 is a sectional view taken along line lil-10 of FIG. 9;

FIG. 11 is a sectional view taken along line 11-11 of FIG. 9;

FIG. 12 is a sectional view taken along line 12-12 of FIG. 9;

FIG. 13 is a plane view of a mass ring having a riding FIG. 14 is a sectional view taken along line 14-14 of FIG. 13; and

FIG. l5 is a sectional view taken along line 15-15 of FIG. 12.

Although the invention is being disclosed in the embodiment of a vertical spin tub automatic washer, it is readily apparent that it is applicable to many other vertical spin containers in centrifuging machines.

Referring now to the drawings and in particular FIGS. 1 and 2, the Washing machine includes a housing or cabinet 1 which completely encloses the various parts of the washing machine and is supported on the base structure 2 which supports the outer tub structure 3. A rotary inner container or tub 4 is mounted Within the outer tub 3 and is provided with an agitator or washing device 5. The agitator 5 is operated by a suitable mechanism (not shown). The rotatable tub and agitator assembly are suitably supported by base structure 2. The base structure affords appropriate resilient mounting (as set forth in K the aforenamed U.S. Patent No. 2,836,083) of the inner tub 4 and associated mechanisms that may `be operated for various typical washing cycles and extraction cycles. The base structure 2 is suitably provided with adjustable legs 6 for leveling the outer or stationary tub 3 and inner or spin tub 4 on a supporting foundation or floor 7. These adjustable legs 6 are provided to maintain the washing machine level with the iloor while tending to prevent any vibrations which may be set up in the machine during operation. Of course, it desired, any suitable locking means may be provided to lock the adjustable legs in the proper position. Access to the inside of the inner or spin tub 4 is provided by a suitable cabinet door 8 supported by hinges 9 on the cabinet top 1G. The door includes a suitable water level control mechanism 11 associated with the agitator cap 12 which controls the fluid ll level for a preselected load. Also, access door 8 houses safety shut ori mechanism 13 which stops or interrupts cycling of the washer whenever the access door 8 is opened, as well as safety latch 14 which activates safety shut off 13 when struck by agitator 5 if excessive gyration occurs during the spin cycle. Furthermore, the washing machine includes stabilizing springs to aid in absorbing energy of gyration and vibration and cooperates with the load equalizer. For a more detailed description of the suitable Washer appertaining to the invention, see U.S. Patent No. 2,836,083, granted to T. R. Smith, assigner to the Maytag Company, May 27, 1958.

Encircling the outer, upper periphery of inner tub 4 are unsymmetrical mass rings 15 as illustrated in FIGS. 3 and 4. The rings 15 are tapered in size, but may be tapered in density to afford an unsymmetrical mass along the peripheral dimension. Mass rings 1S may have a riding rim 16 (shown in phantom). The rings 15 may be made of any suitable material, and also may be merely casings filled with a material to afford the unsymmetrical mass. Rings 1S include a notch 17 for latching purposes as later described. A mass ring 18 is illustrated in FIG. 5 having the mass concentrated as a lblock portion 19 extending over about a third of the mass ring 1S. The ring 18 may have an optional riding rim 20. Mass ring 15 is depicted in FIG. 7 inverted. In this position, the riding ring- 16 is above the center of mass of ring 15.

A group of three or more brackets 21 secured to inner tub 4 support at least two and preferably three mass rings 15 (only a one mass ring support bracket is illustrated in FIG. 6 for simplicity of disclosure although a multiple support bracket for three rings could be used) along riding ribs 22. Brackets 21 are secured to inner tub 4 by simple `bolts and nuts except in areas where mass brake 23 for each ring is provided.

It will be appreciated that one mass brake 23 is provided for each mass ring 15, and they are positioned around tub 4 such that, when applied, mass brakes 23 lock mass rings 15 in a symmetrical pattern to provide equal load distribution of the mass rings in the locked position. This prevents the mass rings from increasing the load unbalance below the critical speed. The mass brakes 23, of course, are adjusted to release above or near the critical speed to permit the mass rings 15 to translate relative to the tub 4 and equalize the load distribution of clothes in the tub 4.

The mass brake illustrated in FIG. 6 comprises a mass body 24 with a locking lug 25 adjacent the mass ring 15 and adapted to engage in notch 17. Bolts 26 with nuts 27 secure the brackets 21 to tub 4 and support mass brake 23 thereon. The mass brakes 23 are biased towards tub 4, or inwardly, by biasing means or springs 28, the bolts 26 extending through apertures 29 in flanges 30 of mass brakes 23. The biasing springs may be adjusted by lock nuts 31. FIG. 8 illustrates the mass ring 18 of FIG. 5 with mass brake 23 applied, and locking lug 25 engaging notch 18a.

In operation of the spin or centrifuging cycle, the mass brake 23 is compressed against biasing springs 28 and releases locking lug 25 from the'notch 17 or 18a by the centrifugal force on the mass brake 23 created by rotation of the mass brake with the spin tub. Once the mass brake releases the unsymmetrical mass rings, the unsymrnetrical mass ring translate about the tub to equalize the load confined in the spin tub 4. As the rotary speed of the spin tub 4 decreases, the centrifugal force on the mass brake and locking lugs 25 engage the mass ring which is rotating faster than the spin tub. Once the notch in the mass ring reaches a position adjacent to the locking lug, the locking lug engages the notch and stops relative rotation between the spin tub 4 and unsymmetrical ymass rings 15 or 18a. With two or more unsymmetrical mass rings being utilized, the washer spin tub and unsymmetrical mass ring forma balanced mass. Thus, the tub itself is initially balanced regardless of any imbalance of the clothes load within the tub.

Referring to FIGS. 8-15, the ensuing description discloses three unsymmetrical mass rings with equidistribution of mass brakes. In FIGS. 9 and l0, three unsymmetrical mass rings 15a 15b and 15C are suspended by riding rims 16 from brackets 21 secured to outer tub 4. Mass brakes 23a, 23b and 23e are distributed around tub 4 and held by bolts 26 and nuts 27 in the same relative position as brackets 21. Mass brake 23a has a mass body 24a with locking lug 25a to engage the uppermost mass ring 15a, mass brake 23b has mass body 24b with locking lug 25b to engage the middle mass ring 15b and mass brake 23e has mass body 24e with locking lug 25e` to engage the lowermost ring 15C. The locking lugs 25a, 25b and 25a` engage notches 17 in mass rings 15a, 15b and 15C. The notches 17 are all at the narrowmost portion of rings 15a, 15b and 15C; hence, position the mass rings 15a, 15b and 15C in an equidistribution of masses pattern whenever engaged. Springs 28 bias respective mass bodies 24a, 24b, and 25C with locking lugs 25a, 25b and 25e` engaging notches 17 in mass rings 15a, 15b, and 15C. The tension or biasing force of springs 28 is adjusted by adjusting the relative positions of bolts 26 and nuts 27, hence, changes the rotary speed of spin tub 4 or centrifugal force at which the brakes release.

In FIG. 10, mass brake 23a is engaged by lug 25a in notch 17 of mass ring 15a. Mass ring 15b has a decreasing taper viewed in FIG. i whereas mass ring 15e` has an increasing taper. In FIG. 1l, mass brake 23b is engaged by lug 25b in notch 17 of mass ring 15b. Mass ring 15a has an increasing taper in FIG. l1 whereas mass ring 15el has a decreasing taper. In FIG. 12, mass brake 23e is engaged by lug 25c in notch 17 of mass ring 15C. Mass ring a has a decreasing taper in FIG. 12 whereas mass ring 15b has an increasing taper. It is apparent from FIGS. ll, l2 and 13 that when the mass brakes 23a, 23b and 23e are engaged the masses of mass rings 15a, 15b and 15e are equally distributed about spin tub 4.

FIGS. 13 and 14 illustrate the characteristic features of mass rings 15a, 15b and 15C described in conjunction with FIGS. 8 through 12.

FIG. 15 illustrates in a fragmentary top view the engagement of mass brake 23e` with mass ring 15C by locking lug 25C in notch 17.

In operation of the three mass ring embodiment described aforesaid, as the spin tub 4 commences rotation and nears the critical speed all three unsymmetrical mass rings 15a, 15b and 15a` are maintained equidistributed about spin tub 4 until mass brakes 23a, 23b and 23C under the influence of mass bodies 24a, 24b and 24a` moving outward under centrifugal force of rotation compress biasing springs 28 disengaging the locking lugs 25a, 25b and 25e of mass brakes 23a, 23b and 23C, respectively, from mass rings 15a, 15b and 15e. The mass rings 15a, 15b and 15a` then rotate or translate relative to spin tub 4 under the tangential component of the rotating centrifugal or unbalance force, if any, to redistribute the masses thereof to equalize the overall load of spin tub 4. Once the load of spin tub 4 is equalized, the tangential component of unbalance force is eliminated since the centrifugal force no longer rotates, and translation of the rings 15a, 15b and 15C stops. The rings 15a, 15b and 15C being freely rotatable relative to the spin tub 4 react dynamically to equalize any load changes during the rotation. \Vhen the spin tub 4 slows its rotary speed, mass brakes 23a, 23b and 23C are biased toward engagement with the mass rings 15a, 15b and 15C. The mass rings 15a, 15b and 15C following the law of motion continue to rotate at a rate faster than the spin tub 4, hence, once the spin tub 4 slows sufliciently for mass brakes 23a, 23b and 23e to engage rings 15a, 15b and 15C, respectively, each mass brake will move into locking engagement as the notches 17 in rings 15a, 15b and 15e pass by locking lugs 25a, 25b and 25C, respectively.

From the foregoing it will be apparent that mass rings 15a, 15b and 15C become disengaged from mass brakes 23a, 23b and 23e during rotation of spin tub 4 to freely translate or rotate and equalize the tub load, and then become reengaged by the mass brakes 23a, 23b and 23C.

Although mass brakes are preferred, they are not absolutely essential, as under the law of motion on initial rotation of spin tub 4, the mass rings would tend to remain at rest until unbalance forces occurred (rotating centrifugal force with a tangential component). Likewise, when spin tub 4 begins to slow, the mass rings would tend to remain in motion in the same relative position with respect to each other. Thus, the free rotation of the mass rings would not greatly effect gyration of the spin tub 4 below critical speed.

It will be app-arent from the foregoing that many changes and modifications may be made to the load equalizer of the invention which will be apparent to those skilled in the art, hence, all such changes are deemed to be within the scope and spirit of the invent-ion which is limited only as necessitated by the scope of the appended claims.

What is claimed is:

1. In a vertical spin, container type centrifugal liquid extractor, a load equalizer comprising support brackets spaced around the periphery of said container, and at least two unsymmetrical mass rings supported by said brackets for unrestricted translation .around the periphery of said container relative thereto.

Z. In a vertical tub, spin extractor type automatic Washing machine, a load equalizer comprising at least three support brackets spaced in each of two different planes around the periphery of said tub, 4and two unsymmetrical mass rings supported by said brackets for continuously free translation around the periphery of said tub relative thereto.

`3. lIn a vertical tub, spin extractor type automatic washing machine, a load equalizer comprising support brackets mounted to said tub around the periphery thereof in three distinct planes, and three unsymmetrical mass rings supported by said brackets for continuously free relative translation `around the periphery of said tub.

4. T he apparatus of claim 3 including for each unsymmetrical mass ring .a centrifugally releasable brake, each of said brakes secured to one of said brackets in each of said distinc-t planes such that when applied said brakes lock their respective mass ring with the total mass equally distributed about said tub limiting free relative translation.

5. The 4apparatus of claim 2 including a centrifugally operated mass brake for each said unsymmetrical mass ring secured to said spin tub, and each said mass brake and each said mass ring having complementary lock-ing means, each said mass brake engaging said complementary locking means to retain all said mass rings arranged in a pattern with equal distribution of the masses of said mass rings about said spin tub below a certain rotary speed of said spin tub 'and each said mass brake disengaging said complementary locking means under the influence of centrifugal force created by rotation of said spin tub at about said certain rotary speed to release each said mass ring for free relative translation about said spin tub to equalize said spin tub load.

6. The lapparatus of claim S wherein each said mass brake engages each said `complementary locking means below the critical rotary speed of said spin tub and disengages each said complementary locking means .at about said critical rotary speed.

7. In a verticaltub, spin extractor type automatic washing machine, a load equalizer comprising support brackets mounted to said tub around the periphery thereof in three distinct planes, three unsymmetrical mass rings supported by said brackets for rela-tive translation around the periphery of said tub, each said mass ring dening a notch in the edge thereof, a centrifugally operated brake for each said mass ring, each said brake having a lug for engaging the notch in each said mass ring, each said mass bnake holding each said lug in each said notch to retain all said mass rings arranged in a pattern with equal distribution of the masses of said mass rings 20 about said spin tub below a certain rotary speed of said spin tub, and each said mass brake disengaging each said lug from each said notch under the influence of centrifugal force created by rotation of said spin tub at about said certain rotary speed to release each said mass ring for free relative translation about said spin tub to equalize said spin tub load.

8. The Iapparatus of claim 7 wherein each said mass brake holds each said lug engaging each said notch below the critical rotary speed of said spin tub and disengages each said lug from eac-h said notch at about said critical rotary speed.

9. The apparatus of claim 7 wherein vsaid mass rings have a tapered mass distribution.

10. The apparatus of claim 7 wherein said mass rings have substantially al1 the mass concentrated uniformly over about a third of the mass ring.

References Cited UNITED STATES PATENTS 331,450 12/1885 -Rothe 74-573 989,043 4/1911l Pohl 74-573 2,186,263 l/ 1940 Morganstern 74-573 2,442,397 6/ 1948 Candor 74-573 2,722,848 11/1955 Stein 74--573 FRED C. MATTERN, In., Primary Examiner.

W. S. RATLIFF, Assistant Examiner. 

7. IN A VERTICAL TUB, SPIN EXTRACTOR TYPE AUTOMATIC WASHING MACHINE, A LOAD EQUALIZER COMPRISING SUPPORT BRACKETS MOUNTED TO SAID TUB AROUND THE PERIPHERY THEREOF IN THREE DISTINCT PLANES, THREE UNSYMMETRICAL MASS RINGS SUPPORTED BY SAID BRACKETS FOR RELATIVE TRANSLATION AROUND THE PERIPHERY OF SAID TUB, EACH SAID MASS RING DEFINING A NOTCH IN THE EDGE THEREOF, A CENTRIFUGALLY OPERATED BRAKE FOR EACH SAID MASS RING, EACH SAID BRAKE HAVING A LUG FOR ENGAGING THE NOTCH IN EACH SAID MASS RING, EACH SAID MASS BRAKE HOLDING EACH SAID LUG IN EACH SAID NOTCH TO RETAIN ALL SAID MASS RINGS ARRANGED IN A PATTERN WITH EQUAL DISTRIBUTION OF THE MASSES OF SAID MASS RINGS ABOUT SAID SPIN TUB BELOW A CERTAIN ROTARY SPEED OF SAID 